Soy-based adhesives with improved lower viscosity

Abstract

The technology is directed towards soy-based adhesive compositions having improved viscosity properties due to the use of soy flour having a particular particle size distribution. These compositions are useful for making lignocellulosic composites or engineered wood products.

We claim: 
     
         1 . An aqueous thermosetting binder composition comprising soy flour slurry and optionally a reactive thermosetting resin; wherein at least 70% of the particles of the soy flour have a particle size of less than about 30 microns. 
     
     
         2 . The binder composition according to  claim 1 , wherein the optional reactive thermosetting resin is a polyamidoamine-epichlorohydrin (PAE) resin. 
     
     
         3 . The composition of  claim 1 , wherein the binder composition further comprises additional additives selected from the group consisting of defoaming aids, acids, bases, buffers, surfactants, viscosity modifiers and adhesion promoters. 
     
     
         4 . The composition of  claim 2 , wherein the ratio of PAE resin to soy flour is from about 1 parts per hundred to about 75 parts per hundred dry soy flour. 
     
     
         5 . The composition of  claim 2 , wherein the ratio of PAE resin to soy flour is from about 5 parts per hundred to about 50 parts per hundred dry soy flour. 
     
     
         6 . The composition of  claim 2 , wherein the ratio of PAE resin to soy flour is from about 8 parts per hundred to about 40 parts per hundred dry soy flour. 
     
     
         7 . A process of producing an aqueous adhesive binder comprising:
 obtaining soy flour slurry, wherein at least 70% of the particles have a particle size of less than about 30 microns; and combining the slurry with at least one reactive thermosetting resin.   
     
     
         8 . The process according to  claim 7 , wherein the reactive thermosetting resin is polyamidoamine-epichlorohydrin (PAE). 
     
     
         9 . The process of  claim 8 , wherein the ratio of PAE resin to soy flour is from about 1 parts per hundred to about 75 parts per hundred dry soy flour. 
     
     
         10 . The process of  claim 8 , wherein the ratio of PAE resin to soy flour is from about 5 parts per hundred to about 50 parts per hundred dry soy flour. 
     
     
         11 . The process of  claim 8 , wherein the ratio of PAE resin to soy flour is from about 8 parts per hundred to about 40 parts per hundred dry soy flour. 
     
     
         12 . A method of making a composite structure comprising applying the aqueous adhesive binder according to  claim 1 , to at least one surface of a lignocellulosic substrate or synthetic substrate; and forming a composite structure. 
     
     
         13 . The composite structure of  claim 12 , wherein the composite structure is made from lignocellulosic substrates. 
     
     
         14 . The process according to  claim 10 , wherein the binder composition is applied by roller coating, knife coating, extrusion, curtain coating, foam coaters and spray coaters.